pef vs dng

John Francis johnf at panix.com
Wed Oct 7 16:19:53 EDT 2009


On Wed, Oct 07, 2009 at 01:31:37PM -0600, steve harley wrote:
> On 2009-10-07 12:46 , P. J. Alling wrote:
>> TIFF format is however very lose, and can accommodate compression
>> schemes that are not commonly used, which would make such files
>> difficult to read at a future date.
>
> i can't digest the specs quickly enough to be sure, but my sense is that  
> TIFF/EP (the ISO standard subset of TIFF which DNG specifically uses) is  
> intended to solve that problem; anyone know for sure?

More to the point, the DNG spec is explicit on the compression scheme
to be used.  IMO that's why we had to wait for the K-7 before Pentax
supported compressed DNGs; although they had coded a compression scheme
for PEFs it didn't use the algorithm called for by the DNG spec, and so
DNGs were written uncompressed.  New firmware in the K-7 fixes that.





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